<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <!-- 统计字符串中的元音子字符串 -->
    <script>
      var countVowelSubstrings = word => {
        let len = word.length
        if (len < 5) return 0
        let count = 0
        for (let i = 0; i < len; i++) {
          for (let j = i + 4; j < len; j++) {
            let arr = new Set(word.slice(i, j + 1))
            if ([...arr].sort().join('') === 'aeiou') count++
          }
        }
        return count
      }
      console.log(countVowelSubstrings('aeiouu'))
    </script>
  </body>
</html>
